With the rapid development of the communication technology, an Optical Transport Network (OTN), which can realize flexible scheduling and management of large-capacity services, is becoming the major technology for a backbone transport network. In order to implement the processing of a client service, the OTN provides mapping processing for various services, such as a GMP for an adaptive constant bit rate service. In the GMP solution, the distribution pattern of client data in a payload is calculated by a predetermined computation rule in real time according to the amount (Cn) of client entities in each frame period to implement the transparent transmission of client signal bit.
In the existing technology, the GMP solution has the following two specific implementation ways:
In one way, which is different from the novel GMP mapping method defined in the G. 709 protocol, firstly, a fixed distribution pattern corresponding to a predetermined client entity amount of client data which is predefined by calculating the predetermined client entity amount is acquired, and a corresponding dynamic distribution pattern is determined for the rest client entity data corresponding to the rest client entities; and secondly, the client data to be transmitted in the current frame period can be mapped according to the fixed distribution pattern and the dynamic distribution pattern.
In the other way, firstly, each low-level ODUj signal is changed into multiple parallel 8b signals, wherein the number of the parallel signals is identical with that of time slots in the Optical channel Data Tributary Unit (ODTU) occupied by the ODUj; secondly, these parallel signals are subjected to GMP mapping separately; and finally, these parallel mapping results are combined together to finish the GMP mapping from the ODUj to the ODTU, and multiple ODTUs are multiplexed to ODU4.
The essences of the two existing technical solutions are both to implement the GMP mapping according to a fixed service rate, so there is still no solution for implementing the GMP mapping according to a dynamic service rate at present.